Electron test tube



1961 w. H. KINGSLEY 2,997,613

ELECTRON TEST TUBE Filed Oct. 13, 1959 IN VEN TOR.

A TTOR/VE Y 2,997,613 ELECTRON TEST TUBE Wayne H. Kingsley, Emporium, Pa., assignor to Sylvania Electric Products Inc, a corporation of Delaware Filed Oct. 13, 1959, Ser. No. 846,120 Claims. (Cl. 3136) This invention relates to electron test tubes for use along with conventional electron tubes during tube manufacture and, if desired, along with and during electron tube life tests on conventional tubes.

The object of the invention is to provide a special electron test tube which shall be manufactured under the same conditions and with the same electrode elements as other tubes of the same type but which test tube has additionally built therein an ionization gauge. By means of this ionization gauge characteristics of a lot of tubes of a type may be accurately determined during manufacture of that lot and, if desired, while random selected tubes of the lot are placed on life test.

In general, the invention comprises a composite tube embodying electrode parts of a regular type electron tube plus an ionization gauge which may comprise a filament, a grid and an anode with leads extending exteriorly of the bulb of the tube.

The composite tube, or several of them, may be processed along with other tubes of the type embodied in the composite tube and while all of the tubes are processed continuous or intermittent measurements are made of the current passing through the ionization gauge, the current passing through the gauge being a function of the gas pressure within the composite tube. By thus monitoring the gas pressure within the test tube under regular tube production, i.e. during exhausting, bombarding of the electrodes, getter flashing, sealing, ageing, etc. and if desired during life tests, various optimum results may be achieved. Among these are: a determination of the best ageing schedule to produce for the tube type the desired electrical characteristics; evaluation of the electrical characteristics of the tube type vs. internal gas pressure during tube life, evaluation of different types of getters; evaluation of different types of materials utilized in the manufacture of the tube; evaluation of different processing schedules, such as cleaning and firing and evaluation of sublimation characteristics under known operating conditions at known gas pressure levels. Also since the ionization of the test tube itself can be measured, the construction thereof permits of ready calibration of the test tube so that under limited use it can act as an ionization gauge.

For a full description of the test electron tube, attention is directed to the following description, taken in conjunction with the single figure of the accompanying drawing in which a test electron tube is shown, partly in section.

The single figure of the drawing shows an envelope 10, cylindrical in cross section, embodying a one end an electrode mount 12 of a selected type of tube, e.g. type 12AU7A.

The tube also comprises the conventional base structure comprising a wafer portion 14 traversed by the leads 16 and which leads are conventionally connected to the electrodes within the tube.

To the mount there is fastened the getter support 18, which may be above the mount or to the left thereof, as viewed in the drawing. Spaced above the mount and along the length of the tube are the electrodes of a conventional high vacuum ionization gauge and which may comprise an oxide coated filament 20, a grid 22, and a plate 24.

To obstruct entering of the getter flash into the section of the tube occupied by the ionization gauge, the dome Patent portion 26 is of a smaller type envelope than the envelope 10 and is supported by a support rod 28 above the getter, this dome portion receiving the flashed getter material; the dome is small enough in diameter to allow free flow of gases past the dome and from one end of the composite tube to the other. In practice, the exhaust tubulation 30, prior to tipping off, is made of a length so that the overall length of the composite test tube, including the tubulation, is of the same overall length as the type of tube being processed, so that the test electron tube can be processed in the same machine wherein the other tubes of the type are processed. Of course the leads 32 from the ionization gauge may be brought out to any convenient exterior portion of the envelope for connection to any convenient track or with spring fingers on the processing machine, but it is preferred to place the leads in a wafer base 34 opposite to the wafer 14 for ease in providing contact with both sets of electrodes within the composite tube. While the composite tube is shown with the exhaust tubulation tipped off at the ionization gauge end, with other types of tubes the tubulation may be in the wafer 14.

For each type of tube desired to be tested, one or more of the electron test tubes are manufactured, each having sealed in at one end the type of mount and lead base of the tube type under test and including if desired the dome portion 26. The portion 26 acts to obstruct the material of the getter when it is flashed from the getter support. Where the getter support is placed along the side of the mount or below the mount (to the right in the figure), there is no necessity for the dome portion. At the other end of the test tube there is sealed in the mount and lead base of the ionization gauge, the base, prior to completion of the tube, being provided with the untipped exhaust tubulation 30. The exhaust tubulation of the test electron tube is placed in an exhaust port of an electron tube exhausting, bombarding and sealing machine just as are the tubulations of the conventional tubes of the type being manufactured and the machine is indexed as usual. Since the overall height of the test tube and of the other tubes are the same and the regular tube mounts are all at the same end of the bulbs, the test electron tube mount 12 will be processed like all the rest of the tubes. But, during processing and subsequent ageing and life tests desired ionization measurement may be made on the test tube and records made of the results for subsequent valuation.

Having thus described the invention, what is claimed is:

l. A test electron tube comprising an envelope containing an ionizable gas, an electrode mount having electrodes comprising at least an anode and a cathode, an associated lead base at one end of the envelope said base having leads connected with said electrodes, an ionization gauge comprising at least an anode and a cathode having an associated lead base at the opposite end of the envelope with leads from said second lead base connected to said electrodes of the ionization gauge, the envelope being provided with a tipped off evacuation tubulation at the ionization gauge base end or" the envelope.

2. A test electron tube comprising a cylindrical envelope containing an ionizable gas, an electrode mount and associated lead base at one end of the envelope, an ionization gauge and associated base at the opposite end of the envelope, with the envelope tipped off by evacuation tubulation at the ionization gauge base, said mount including a support initially carrying a getter, and a dome shaped getter flash obstructor between the getter support and the ionization gauge, said obstructor being supported by the mount and spaced from the walls of the envelope to permit free movement of the gases within the envelope.

3. A test electron tube comprising an elongated envelope containing an ionizable gas, said envelope having opposed parallel bases through each of which a set of leads extends, an electrode mount having electrodes comprising at least an anode and a cathode within the en-. velope and connected with one set of leads, and an ionization gauge within the same envelope and having electrodes comprising at least an anode and a cathode connected with the opposite set of leads.

4. A test electron tube comprising an elongated envelope containing an ionizable gas and having opposed parallel bases through each of which a set of leads extends, an electrode mount within the envelope and having electrodes comprising at least an anode and a cathode, said electrode mount being near one base and connected with the leads extending through that base, and an ionization gauge within the same envelope having electrodes comprising at least an anode and a cathode and near the opposite base, said ionization gauge electrodes being connected with the leads extending through said opposite base.

5. A test electron tube comprising an elongated envelope containing an ionizable gas, said envelope having opposed parallel bases through each of which a set of leads extends, an electrode mount within the envelope, said mount comprising at least an anode and a cathode connected with one set of leads, an ionization gauge within the same envelope spaced from the mount, said gauge having electrodes comprising at least an anode and a cathode with the ionization gauge electrodes connected with the opposite set of leads, said electron mount having a support initially carrying a getter, and a getter flash obstructor supported by the electrode mount, the obstructor being located between the getter support and the gauge.

6. A test electron tube comprising a cylindrical envelope containing an ionizable gas and having opposed parallel bases through each of which extends a set of leads, an electrode mount having electrodes comprising at least an anode and a cathode adjacent one end of the envelope With the electrodes connected with the set of leads extending through the adjacent base, an ionization gauge adjacent the other end of the envelope and having electrodes comprising at least an anode and 'a cathode with said ionization gauge electrodes connected with the set of leads extending through the opposite base, a support initially carrying a getter mounted in the envelope near the mount, and a getter flash obstructor mounted within the envelope between the ionization gauge and the mount with its nearby getter support said obstructor being spaced from the cylindrical wall of the envelope to allow free flow of ions throughout the envelope.

7. A test electron tube comprising an envelope containing an ionizable gas, an electrode mount having electrodes comprising at least an anode and a cathode, an associated lead base at one end of the envelope having 4 leads connected to said electrodes, and an ionization gauge comprising, at least, an anode and a cathode at the opposite end of the envelope, and leads at said opposite ends of the envelope extending from the cathode and anode of said ioniztaion gauge through said opposite end of the envelope and to the exterior thereof.

8. A test electron tube comprising an envelope including an ionizable gas, an electrode mount having at least an anode and a cathode at one end of the enevlope, an associated lead base at said end of the envelope having leads connected to said electrodes, and an ionization gauge comprising, at least, an anode and a cathode at the opposite end of the envelope with leads from said cathode and anode extending through said opposite end of the envelope to the exterior thereof, the envelope being provided with a tipped off evacuation tubulatiou at the ionization gauge and of the envelope.

9. A test electron tube comprising a cylindrical envelope containing an ionizable gas, an electrode mount and associated base lead at one end of the envelope, an ionization gauge comprising, at least, an anode and a cathode and associated base at the opposite end of the envelope, said mount including a support initially carrying a getter, and a dome shaped getter flash obstructor between the getter support and the ionization gauge, said obstructor being supported by the mount and spaced from the Walls of the envelope to permit free movement of gases within the envelope.

10. A test electron tube comprising a cylindrical envelope containing an ionizable gas and having opposed parallel bases through each of which extends a set of leads, an electrode mount adjacent to one end of the envelope and connected with the set of leads extending through the adjacent base, an ionization gauge comprising at least an anode and a cathode adjacent the opposite.

end of, the envelope and connected with the set of leads extending through the opposite base, a support initially carrying a getter mounted in the envelope nearby the mount, a getter flash obstructor mounted with the envelope between the ionization gauge and the mount with its nearby support, said obstructor being spaced from the cylindrical walls of the envelope to allow free flow of ions throughout the envelope.

References Cited in the file of this patent UNITED STATES PATENTS 1,334,143 Dushman Mar. 16, 1920 1,566,279 King Dec. 22, 1925 2,082,851 Smith June 8, 1937 2,112,082 Espe Mar. 22,1938

2,502,070 Atlee Mar. 28, 1950 FOREIGN PATENTS 203,681 Australia Dec. 9, 1954 

